Inclusion of fish bone and crab by-products in diets for Atlantic cod, Gadus morhua

Summary

The effect of dietary inclusion of fish bone and crab by-products on growth performance and feed utilization was investigated in a growth trial with Atlantic cod. High quality fish meal was used as a control. Fish meal was replaced with fish bone meal at 150, 300 and 450 g kg−1, while dietary inclusion level of a crab by-product meal was 54, 115 and 176 g kg−1. Dietary protein and lipid were kept constant at 500 and 180 g kg−1 for all diets. The contents of ash in the diets were 84 g kg−1 for the control and 117, 148 and 180 g kg−1 for the fish bone meal and crab meal based diets. The feeding trial lasted 95 days, and average fish weight increased from 196 g initial weight to a final weight of about 500 g. The growth experiment showed a linear increase in feed intake with increasing dietary ash, resulting in a similar linear increase in growth measured by weight gain, SGR and TGC. The increase in growth was about 10% when the dietary ash level was increased from 84 to 180 g kg−1. For the fish bone meal based diets, no effect was observed on digestibility of protein and lipid, feed efficiency ratio, protein efficiency ratio or protein productive value. The crab meal based diets showed a similar picture, however, cod fed the highest level of crab meal had a lower feed efficiency ratio, protein efficiency ratio and protein productive value compared to the other groups. The results indicate that diets for cod can beneficially contain at least 180 g kg−1 ash from fish bone and 150 g kg−1 from crab meal. This opens the possibility to use unutilized by-products from the fish industry as cost effective and valuable feed ingredients for cod. © 2005 Elsevier B.V. All rights reserved.